Under this view, there is no such thing as objective morality, and thus no objective good and bad. It's all about opinions and that's all it ever could be about. The fact that you're "wired" to avoid pain doesn't imply it's good to do so.
The fact that atheists still, on the whole, want good things to happen to themselves and to other people is an often-overlooked leap of faith.
I'm not sure how that follows. Atheists are writed to to avoid pain and stimulate pleasure centers, those things are directly influenced by their actions, which just happen to correlate with "good" and "bad"" (or, more correctly, opinions of what's good and what's bad are based on those stimulations), and thus atheists want good things to happen, simply because the are wired like that. Why does faith have to enter into this?
I'm saying it's a leap of faith if you believe the Universe is inherently meaningless. Saying it's meaningless but then giving your own desires and sufferings any significance is just a non-sequitur. There can be no logical justification for anything in a meaningless Universe. If you assert that set x is meaningless and set x contains set y, set y is therefore also meaningless. You should have no business talking about what's good or bad for you in a meaningless Universe.
Saying you 'just happen' to be wired a certain way is like saying it 'just happens' that everything in the Universe adheres to mathematical laws...as if it were some kind of fluke. Given that mathematical laws are meaningful, it's self-evidently the opposite.